In a finding that may change scientific understanding of the evolution of female sex hormone 'progesterone', scientists have claimed to have found the hormone in a plant.
Until now, scientists thought that only animals could make progesterone -- a steroid hormone secreted by the ovaries
-- which prepares the uterus for pregnancy and maintains it. A synthetic version, progestin, is used in birth control pills and other medications.
"The significance of the unequivocal identification of progesterone cannot be overstated," said the study by a team led by Guido F Pauli at the College of Pharmacy, Chicago.
"While the biological role of progesterone has been extensively studied in mammals, the reason for its presence in plants is less apparent," it said.
Though scientists had previously identified progesterone like substances in plants and speculated that the hormone itself could exist in plants, they had not found the actual hormone in plants until now.
Pauli and his colleagues used two powerful laboratory techniques, nuclear magnetic resonance and mass spectroscopy, to detect progesterone in leaves of the Common Walnut, or English Walnut, tree.
They also identified five new progesterone-related steroids in a plant belonging to the buttercup family.
Following the discovery, published in ACS Journal of Natural Products, the scientists believe the hormone, like other steroid hormones, might be an ancient bioregulator that evolved billions of years ago, before the appearance of modern plants and animals.